This proposal aims to do a feasibility study on the use of enzyme coated thermistors as glucose sensors to in type I diabetes. The applicant and his group have previously done a considerable amount of work on the development of such sensors albeit for a different purpose and they find the thermistor has a number of advantages over the electrode-type sensors presenting being promoted. The overall aim is to covalently immobilize a combination of glucose oxidase and catalase onto a micro-thin layer of a suitable coating that has been applied to the glass body of the thermistor. Several possible co- polymers are presently being investigated for stability as a coating. Glucose oxidase isolated from P. notatum, which has been reported to have a very low Km for Oxygen, will be use to try to overcome the "oxygen deficit" problems encountered with use of the enzyme from A. niger. After the enzyme is successfully immobilized on the thermistor, the kinetic and physical properties of the sensors will be investigated in vitro. Then a stability study of the enzyme-thermistors in vivo will be conducted in rabbits, both subcutaneously and intravenously to measure response time to sudden changes in blood glucose levels. The electronic instrument and the computer program needed to process the signals from the thermistors have already been designed at the National Institutes of Health, an a prototype instrument in the P.I.'s laboratory will be used in this projects.